A retired heart surgeon saved the life of a police officer with just three minutes to spare after he had been stabbed in the throat by a crazed knifeman.
Samad Tadjkarimi stemmed the flow of blood with his bare hands after finding Pc Paul Madden bleeding to death in the street.
The officer was attacked by career criminal John Onyenaychi near a bus stop in Ealing last December.
Mr Tadjkarimi, 65, was returning from Christmas shopping when he saw the 23-year-old officer with 'horrendous injuries' which medics say would have killed him within the next three minutes.
Mr Tadjkarimi said: 'I noticed an officer lying on the pavement — lots of blood on the right side of his neck. I compressed his neck, holding it.
'Although he looked pale, obviously due to the volume of blood lost, he was calm. I reassured him that he would be fine and the ambulance would be there any second.'
Onyenaychi was jailed today for a minimum of 25 years for the attack on Pc Madden and a police support officer who tried to help him.
Onyenaychi, 30, cut Pc Madden's throat as people watched in horror in New Broadway.
He then lashed out with his knife at other officers who attempted to restrain him, the Old Bailey heard. He called out: 'Let me finish him off.'
The retired surgeon was reluctant to be hailed a hero. He said: 'I am very pleased he survived. It’s very humbling that my intervention perhaps contributed to the outcome of possibly saving his life — a very brave young officer.'

Heroic: Samad Tadjkarimi halted the blood flowing from Pc Paul Madden's throat, saving his life with just three minutes to spare:

John Onyenaychi (left) has been jailed for life for trying to kill Pc Madden:

Pc Madden, pictured here outside today's hearing at the Old Bailey:

Bloody aftermath: Onyenaychi slashed Pc Madden's throat with a knife in front of horrified onlookers in New Broadway, Ealing, then begged to be allowed to 'finish him off' as officers tried to restrain him:

He added: 'It’s my duty, I guess. I’m sure anyone in my profession would do the same.'
When asked what was going through his mind as he used his hands to stem the blood, he said he thought of his own family. He said: 'He was the same age, virtually, as my son.'

Mr Tadjkarimi also helped PCSO Piotr Dolata, 27, who needed 12 stitches to his head.
'I saw a young officer, blood pouring from his face, with blood also spurting from his scalp,' said Mr Tadjkarimi.
He put pressure on the six-inch cut and bandaged it with the help of members of the public.
Fellow PCSO Steven Constable was slashed twice, but escaped serious injury because his high-visibility jacket saved him.
Mr Tadjkarimi came to the UK in 1973 after completing his medical training in Istanbul. His 21-year-old son, a medical student, is following in the footsteps of both parents, as his mother is also in the profession. Mr Tadjkarimi joked: 'It must be in the genes.'
Onyenaychi, of Wise Road, Stratford, east London, was found guilty of two counts of attempted murder, causing grievous bodily harm with intent, robbery and attempting to cause grievous bodily harm.

Bearing the scars: A computer-generated handout shows the injuries Pc Madden sustained to his head and neck, while PCSO Piotr Dolata needed 12 stitches to his head after he was also attacked by Onyenaychi:

During the trial, the Old Bailey heard that four days before the attack on the officers, Onyenaychi had stabbed Muhammad Memon five times in a cab office in Greenford.
Mr Memon had been an innocent bystander as Onyenaychi had sought out a cab driver, who he had earlier tried to rob.
Onyenaychi grabbed him by the neck and threatened to kill him at knifepoint, the court heard.
The driver managed to escape into the office, where Onyenaychi attacked Mr Memon.
Brian Altman, prosecuting, said Onyenaychi had gone to the office to get his mobile phone which he had left in the cab during his attempt to rob the driver earlier that day.
Two days later Onyenaychi arranged to meet the cab driver through Gumtree to discuss buying a laptop and returned to the seller’s address in Fulham to complete the deal.
Mr Altman said: 'Following the excuse to use the lavatory he emerged and produced a knife with which he threatened to kill him unless he handed over the laptop computer.'
He fled with the laptop and an iPhone.